Push-in type W-base retainers are used in a variety of connection assemblies to secure components of the assembly. For example, in automobiles such stud-like retainers are used to secure molding or other surface structures to underlying support elements such as body panels, support beams or the like. Such retainers typically include a stem with deflectable wing elements for securing the retainer to the support elements when the stem portion supporting the deflectable wing elements is pushed through an aperture in the support element. Typically, a head attached to the stem is configured for attachment to a doghouse or other complementary receiving element on the underside of the surface structure. In this regard, the head may include an enhanced diameter upper platform radial collar feature and an enhanced diameter lower radial collar feature with a spacing post extending between the upper and lower radial collar features. Thus, the spacing post may slide into a doghouse or other receiving element as will be well known to those of skill in the art and thereafter be blocked against axial withdrawal by the upper and lower radial collar features.
During use, as the stem is inserted into the aperture, the deflectable members may be compressed radially inwardly. The deflectable members then may spring outwardly as insertion is completed to lock behind the underside of the support element. Thus, with the head secured to the surface structure, the retainer forms a connection between the surface structure and the underlying support element.
W-base retainers are typically designed as a component of an overall assembly and work in conjunction with the other components with the goal of establishing and maintaining a “zero gap” condition between the sheet metal panel or other support element and the molding or other surface structure. To promote the desired “zero gap” condition, the W-base retainers typically provide a continuous pull down or clamp load condition. This constant pull down is intended to provide and maintain the desired “zero gap” condition between the support element and the molding or other surface structure. If this pull down force is compromised by a significant force acting in the opposite direction such that the molding or other surface structure does not seat against the sheet metal panel or other support element, an unacceptable gap condition may occur within the final assembled product. Such a gap condition may result in undesired rattling noise as well as in the introduction of dirt and water between the molding or other surface structure and the underlying support structure.
As much as is reasonably possible, it is generally desirable to limit the generation of squeaks, rattles and objectionable noises that may be created from movement of the retainer relative to the parts to which it is connected. By way of example only, and not limitation, various sealing arrangements for push through retainers are illustrated and described in U.S. Pat. No. 5,173,026 to Cordola et al. and US published application 2006/0099051 to Moerke, the contents of all of which are incorporated herein by reference in their entirety. To minimize corrosion, it is desirable also to prevent moisture from precipitation, carwashes, etc. from seeping past the retainer, and through the aperture in which the retainer is installed.
A variety of sealing structures have been used to minimize rattles and squeaks and to prevent moisture seepage past the retainer. Independent concave skirts such as described in US published application 2006/0099051 have been used in conjunction with push-in retainers at the base of the head to confront the body panel around the aperture in the panel. Elastomeric and foam seals also have been used to further improve sealing qualities against moisture penetration.
Although retainers as described incorporating concave skirts and/or seals have been used successfully to limit squeaks and rattles and to inhibit the penetration of moisture past the retainer, further improvements are desirable. Installing the seal as a separate part is cumbersome and awkward, complicating installation of the retainer. If installed on the retainer in advance, the seal can become dislodged, even if properly placed on the retainer. In automated assembly plants, a retainer missing a seal may not be detected and may be installed on the article in which it is used inadvertently. A loose retainer of this type will rattle or squeak, may provide a path for the penetration of moisture and may not adequately secure the second article or item as required. If the seal is adhered to the skirt of the retainer, the seal may not function optimally if the retainer is not seated squarely in the panel. Further, the position of the seal relative to the retainer skirt has limited the range of panel thicknesses with which the retainer can be used effectively to provide a seal against moisture intrusion.
As will be understood by those of skill in the art, a seal which is held between the retainer head and the support panel may experience a build, stack up condition as compression force is applied which results in a counteracting upward force being applied against the head which may partially offset the pull-down force provided by the deflectable wings. In some cases, the presence of seal elements which are compressed between the retainer head and the support panel may block the lower collar feature of the retainer from getting close enough to the underlying sheet metal panel to establish the desired “zero gap” condition between the sheet metal panel and the overlying molding or other surface structure. That is, the compressed seal in stack-up condition may act in the manner of a spacing shim holding the retainer head further away than intended from the sheet metal panel or other underlying support element. With the retainer head in this elevated condition, the attached molding or other surface element will likewise be held away from the panel or other support element and a gap condition may result.